Compliance
Compliance Guide: Navigating the New Tax Adviser Registration Rules
New mandatory rules for tax advisers are here—learn what’s changed, who’s affected and how to comply by the deadlines.
By NomadicTax Research Team • 5 min read • September 11, 2026
## Who Needs to Register Under MMTAR?
The Modernising and Mandating Tax Adviser Registration (MMTAR) framework requires certain tax advisers to register with HMRC through the **Agent Services Account (ASA)**. The second registration phase is currently open: advisers with Self-Assessment or Corporation Tax accounts and no ASA must register by **18 November 2026**. ([gov.uk](https://www.gov.uk/government/news/second-registration-window-now-open-for-tax-advisers?utm_source=openai))
Exemptions include advisers who only offer payroll services and some financial service organisations (with further deadlines for those groups still to come). Agencies should verify whether they fall within scope via HMRC’s interactive tools.
## How to Register & Key Steps
- Go to GOV.UK and use self-serve tools to check your status.
- Set up an ASA (free, online) if you don’t already have one.
- Gather required information—identity verification, proof of qualification, and any professional body affiliations.
- Complete registration before deadline to avoid disruption to operating on behalf of clients.
## Risks of Non-Compliance
- Loss of ability to represent clients with HMRC, especially for Self Assessment or Corporation Tax.
- Potential reputational damage and penalties for advising without meeting HMRC requirements.
- Clients could be affected—returns rejected or filings delayed.
## Practical Example
Rob is a freelance tax adviser who prepares Self Assessment returns for small landlords. He doesn’t use ASA yet.
- He must register under phase two by 18 Nov 2026.
- He accesses his existing Self Assessment account and submits the ASA registration, including verifying identity and professional credentials.
- He checks whether fringe exemptions apply to his practice.
## Supporting Changes via HMRC Roadmap
These registration rules are part of wider HMRC transformation objectives: simplifying Self-Assessment registration/deregistration, enhancing digital services, improving user communication via text and email confirmations, and expanding app-based functionalities. ([gov.uk](https://www.gov.uk/government/publications/hmrc-transformation-roadmap-progress-update-2026/hmrc-transformation-roadmap-update-2026?utm_source=openai))
## Action Checklist
- Register for ASA if required **before 18 Nov 2026**.
- Keep professional credentials up to date and maintain records of necessary qualifications.
- Subscribe to HMRC updates—changes may apply to your next advising category (payroll-only, financial sector).
- Understand what permissions and client interactions you’re allowed while awaiting registration approval.
Stepping through these changes carefully ensures you stay compliant, preserve your ability to represent clients, and avoid sanctions.